There are many ways to get backlinks. Backlinks vary in value as well. The more valuable links can be harder to get for your website.
There are mainly two kinds of backlinks. There are one-way and two-way. Your site gets a one-way link if a website links to you and you do not link back. So that means you can not do link exchanges if you want the valuable backlinks. To get these more valuable links you must have a great website full of rich content. That shows other webmasters that your site has value and they link to you may be to give their readers a great resource. Another way is to buy them which is the most common.
Website owners may charge upwards of $20 a month to display your link on their very popular website. It may seem like a lot but it is worth it because if they put it in a nice spot where the visitors can easily see it then they will visit your site by clicking on the link.
The way to get really good search engine rankings is to have high valued sites link to yours. Websites with a high page rank can be very beneficial. When it comes to backlinks it goes quality before quantity. What I mean is that a site with less links with more value will rank higher than a site with more links and less value.
Getting top quality links is also beneficial because it increases your page rank. The point I am trying to make is that you want to get as many high-quality backlinks as possible to get maximum exposure for your site. That way make as much money as you can handle.